For the cake: Preheat the oven to 350 degrees F. Spray a football cake pan with nonstick cooking spray and put on a baking sheet.

Prepare one of the cake mixes according to the package instructions. Pour the batter into the prepared pan and bake until a toothpick inserted into the center comes out clean, about 50 minutes. Let cool in the pan for about 20 minutes, then remove from the pan to a cooling rack. Repeat with the second cake mix to make another football cake layer.

Level each cake: Using a serrated knife, slice the uneven top of each cake to create a smooth, flat, even surface. Leave one cake trimmed-side up and flip the other cake over so the domed football shape/side is facing up.

For the mouth: The mouth should be oriented 2 inches from the tip of the cake. On the cake half with the domed football shape facing up, measure about 2 1/2 inches from the pointed end of the football down toward the center. This point will be the top of the mouth. From that point, using a paring knife, carefully outline a half oval or crescent shape to form a mouth. The mouth opening should be roughly 6 inches wide and 3 1/2 inches from top to bottom. The edge points of the mouth should be about 1/2 inch from the edge of the cake. Once you have created an outline, go back and cut into the outline about halfway down into the cake. Carefully remove the cut-out piece to form the mouth. Scoop out some of the cake with a spoon if needed to make the mouth deeper.

To assemble, frost and decorate: Transfer 1 3/4 cans of white frosting to a disposable pastry bag fitted with a medium round tip (or cut off the tip of the bag to create about a 1/2-inch opening).

For the blue-grey frosting (shark back): Mix together 1 can of frosting with the black gel food coloring and 5 drops of the blue gel food coloring. Mix until uniform in color. Transfer to a disposable pastry bag fitted with a medium round tip (or cut off the tip of the bag to create about a 1/2-inch opening).

For the red frosting (shark jaw): Combine 1/4 can of frosting with 10 to 15 drops of red gel food coloring. Mix until uniform in color. Transfer to a disposable pastry bag fitted with a medium round tip (or cut off the tip of the bag to create about a 1/2-inch opening).

For the blue frosting (water): Mix together 1 can of frosting with the remaining 5 drops of blue gel food coloring. Mix until uniform in color. Transfer to a disposable pastry bag fitted with a medium round tip (or cut off the tip of the bag to create about a 1/2-inch opening).

Pipe a layer of white frosting on the flat top of the football cake layer (the layer without the mouth cut out) and spread the frosting with an offset spatula. Place the other cake layer with the mouth cut out flat-side down on top to form a football-shaped cake. Slice off 4 inches from the tip of the bottom of the cake to create a flat bottom. Pipe some frosting in the center of a 12-inch cardboard cake round. Carefully stand the cake upright, flat-bottom down, onto the frosting on the cardboard cake round.

Apply a thin crumb coat of white frosting over the entire cake except in the cut-out mouth. Smooth out the frosting with an offset spatula. Place in the freezer for 30 minutes to harden the frosting.

Pipe the white frosting on the bottom/belly of the shark around the mouth and smooth it out with an offset spatula. Pipe the blue grey frosting on the top/back of the shark and smooth out with an offset spatula. Pipe the red frosting around the perimeter of the mouth to create jaws.

Insert the pumpkin seeds and slivered almonds in rows into the red frosting to form the teeth. Press the chocolate-covered mint candies on either side of the shark into the grey frosting to form the eyes. Dab a little white frosting on each eye to create a reflection. Towards the top of the shark head/nose, press the end of a chopstick into the white frosting to make 2 nostril holes.

Pipe blue and white frosting around the base of the shark cake to create water and white-tipped waves around the shark. Sprinkle the white sugar pearls onto the white frosting to mimic little bubbles.